Files
RustPython/tests/snippets/stdlib_itertools.py
2019-08-17 19:32:49 +09:00

203 lines
3.9 KiB
Python

import itertools
from testutils import assertRaises
# itertools.chain tests
chain = itertools.chain
# empty
assert list(chain()) == []
assert list(chain([], "", b"", ())) == []
assert list(chain([1, 2, 3, 4])) == [1, 2, 3, 4]
assert list(chain("ab", "cd", (), 'e')) == ['a', 'b', 'c', 'd', 'e']
with assertRaises(TypeError):
list(chain(1))
x = chain("ab", 1)
assert next(x) == 'a'
assert next(x) == 'b'
with assertRaises(TypeError):
next(x)
# itertools.count tests
# default arguments
c = itertools.count()
assert next(c) == 0
assert next(c) == 1
assert next(c) == 2
# positional
c = itertools.count(2, 3)
assert next(c) == 2
assert next(c) == 5
assert next(c) == 8
# backwards
c = itertools.count(1, -10)
assert next(c) == 1
assert next(c) == -9
assert next(c) == -19
# step = 0
c = itertools.count(5, 0)
assert next(c) == 5
assert next(c) == 5
# itertools.count TODOs: kwargs and floats
# step kwarg
# c = itertools.count(step=5)
# assert next(c) == 0
# assert next(c) == 5
# start kwarg
# c = itertools.count(start=10)
# assert next(c) == 10
# float start
# c = itertools.count(0.5)
# assert next(c) == 0.5
# assert next(c) == 1.5
# assert next(c) == 2.5
# float step
# c = itertools.count(1, 0.5)
# assert next(c) == 1
# assert next(c) == 1.5
# assert next(c) == 2
# float start + step
# c = itertools.count(0.5, 0.5)
# assert next(c) == 0.5
# assert next(c) == 1
# assert next(c) == 1.5
# itertools.repeat tests
# no times
r = itertools.repeat(5)
assert next(r) == 5
assert next(r) == 5
assert next(r) == 5
# times
r = itertools.repeat(1, 2)
assert next(r) == 1
assert next(r) == 1
with assertRaises(StopIteration):
next(r)
# timees = 0
r = itertools.repeat(1, 0)
with assertRaises(StopIteration):
next(r)
# negative times
r = itertools.repeat(1, -1)
with assertRaises(StopIteration):
next(r)
# itertools.starmap tests
starmap = itertools.starmap
assert list(starmap(pow, zip(range(3), range(1,7)))) == [0**1, 1**2, 2**3]
assert list(starmap(pow, [])) == []
assert list(starmap(pow, [iter([4,5])])) == [4**5]
with assertRaises(TypeError):
starmap(pow)
# itertools.takewhile tests
from itertools import takewhile as tw
t = tw(lambda n: n < 5, [1, 2, 5, 1, 3])
assert next(t) == 1
assert next(t) == 2
with assertRaises(StopIteration):
next(t)
# not iterable
with assertRaises(TypeError):
tw(lambda n: n < 1, 1)
# not callable
t = tw(5, [1, 2])
with assertRaises(TypeError):
next(t)
# non-bool predicate
t = tw(lambda n: n, [1, 2, 0])
assert next(t) == 1
assert next(t) == 2
with assertRaises(StopIteration):
next(t)
# bad predicate prototype
t = tw(lambda: True, [1])
with assertRaises(TypeError):
next(t)
# StopIteration before attempting to call (bad) predicate
t = tw(lambda: True, [])
with assertRaises(StopIteration):
next(t)
# doesn't try again after the first predicate failure
t = tw(lambda n: n < 1, [1, 0])
with assertRaises(StopIteration):
next(t)
with assertRaises(StopIteration):
next(t)
# itertools.islice tests
def assert_matches_seq(it, seq):
assert list(it) == list(seq)
i = itertools.islice
it = i([1, 2, 3, 4, 5], 3)
assert_matches_seq(it, [1, 2, 3])
it = i([0.5, 1, 1.5, 2, 2.5, 3, 4, 5], 1, 6, 2)
assert_matches_seq(it, [1, 2, 3])
it = i([1, 2], None)
assert_matches_seq(it, [1, 2])
it = i([1, 2, 3], None, None, None)
assert_matches_seq(it, [1, 2, 3])
it = i([1, 2, 3], 1, None, None)
assert_matches_seq(it, [2, 3])
it = i([1, 2, 3], None, 2, None)
assert_matches_seq(it, [1, 2])
it = i([1, 2, 3], None, None, 3)
assert_matches_seq(it, [1])
# itertools.filterfalse
it = itertools.filterfalse(lambda x: x%2, range(10))
assert 0 == next(it)
assert 2 == next(it)
assert 4 == next(it)
assert 6 == next(it)
assert 8 == next(it)
with assertRaises(StopIteration):
next(it)
l = [0, 1, None, False, True, [], {}]
it = itertools.filterfalse(None, l)
assert 0 == next(it)
assert None == next(it)
assert False == next(it)
assert [] == next(it)
assert {} == next(it)